If $CO_2$ is released during respiration,why does the concentration of $CO_2$ in the atmosphere remain relatively constant?

Which of the following factors is essential for photosynthesis?

Consider the following statements regarding photosynthesis:
$(A)$ $ATP$ formation during photosynthesis is termed as photophosphorylation.
$(B)$ Kranz anatomy pertains to leaf.
$(C)$ Reduction of $NADP^+$ to $NADPH$ occurs during Calvin cycle.
$(D)$ In a chlorophyll molecule,magnesium is present in the phytol tail.
Which of the above statements are correct?

$CO_2$ is formed in all of the following except:

Assertion : Dark reaction occurs only at night in the stroma of chloroplast.
Reason : $CO_2$ fixation occurs only during $C_3$ cycle.

$I.$ Photosystem-$I$ is a photosynthetic pigment system located on the appressed part of grana and thylakoids.
$II.$ Photosystem-$II$ is a photosynthetic pigment system located on the non-appressed part of stroma only.
Identify whether the given statements are correct or incorrect and choose the correct option accordingly.